In whole blood, it is known that there are a small minority of cells that can play an important role in a metastasis of a disease or can be used as a biomarker, which are called rare cells, compared to conventionally known blood cells such as red blood cells, white blood cells, and platelets.
Circulating tumor cells (CTC) are representative of rare cells, and it is known that one or two CTCs exist in several billions of blood cells. When many CTCs are found, it can be a very critical clue for determining the possibility of diagnosing cancer through a blood test, and thus various blood test methods using the CTCs are being developed.
Recent clinical papers and related techniques show that CECs can be used as a biomarker in an early diagnosis of cardiovascular diseases such as a heart attack, and therefore CTC-like or related techniques are being rapidly developed.
For example, in “Characterization of circulating endothelial cells in acute myocardial infarction,” from Science Translational Medicine which was published on March, 2012, it was disclosed that a cardiovascular diseases group had about five times the CECs of a healthy group, and it was reported that an increase in the number of such CECs over a predetermined number may lead to a diagnosis of a risk of a heart attack within 2 weeks.
The cells such as CTCs or CECs are very difficult to isolate or detect by a common technique since very few exist, and they are very critical rare cells involved in two major causes of human death, for example, cancer and cardiovascular disease. This technique for the detection of such cells may be difficult, but in that it can test for cancers and cardiovascular diseases by only providing a small amount of blood (7.5 ml) from the patient's perspective, it is a very innovative technique that has a market waiting for it.
The currently known method of detecting CTCs or CECs is a method of detecting rare cells using an antigen-antibody reaction, which has very high selectivity. That is, a surface of a nano particle having magnetic property is coated with antibodies that can be attached in response to antigens of specific rare cells, and mixed with a blood sample by stirring, thereby the nano particles are attached to the specific rare cells which exist in the blood. Then, they are tightly fixed using a magnetic force, and washed to remove remaining cells, thereby isolating only the specific rare cells. The isolated rare cells may be verified by staining under a microscope, and then cells in each sample may be enumerated.
However, such conventional methods require separate processes such as a pretreatment and a post treatment, and such processes take a very long time. Also, to handle such processes, a skillful examiner is definitely necessary, and therefore, it is very difficult to use the conventional methods in a clinical setting. Accordingly, in order to be rapidly used in the clinical setting, examination should be simple and fast, and in order to easily perform examination by medical personnel, a quantified and objectified apparatus and method for detection are required.